I'd be interested to know if anyone on HN has actually done that in the past, and what the experience was?
Confiks managed to get Spotify to reinstate the API that allowed connections to SongShift with a GDPR complaint about the right to data portability (or threat thereof): https://news.ycombinator.com/item?id=24764371
Better to just contact NOYB directly, they are responsible for about 50% of all GDPR fines to date. Outside of Norway the DPAs seem mostly useless, especially when it comes to big tech…